1. Field of the Invention
The present invention relates to a monitor for detecting a plurality of optical signals, and in particular, a monitor for laser shock processing that detects the absence, presence, or other quality of an optical signal from an array of optical signals.
2. Description of the Related Art
Lasers are composed of various optical components, and light and photon generating devices. Light is generated by various laser components such as flashlamps and the energized gain medium. Light can also be reflected, scattered, and/or transmitted from optical components such as lenses and mirrors. These various light sources produce optical signals.
Optical signals may be generated within a laser by various means. Photons from these optical signals may be detected. An optical signal could be generated by photons which directly reflect (i.e. specular reflection) off the surface of a laser component or workpiece being processed. In addition, an optical signal may be generated due to diffuse reflection (i.e. non-specular scattering of photons in all directions). An optical signal may also be generated by photons that xe2x80x9cleakxe2x80x9d through a mirror in which photons are transmitted through rather than being reflected by the mirror. Further, an optical signal may be generated by a portion of the laser beam hitting a non-optical surface, for example, a beam dump or energy meter.
Additionally, an optical signal may be generated by an electrical or magnetic signal, such as an LED or other light-emitting device. One light-emitting device which may be employed is a material that emits light at a wavelength other than the laser wavelength, such as known fluorescent materials. This light-emitting material may be an absorbing material (perhaps used as a beam dump) or a transmitting material, such as a doped optical material.
In order to monitor the presence of an optical signal, (i.e. light produced by a light generating source which includes light reflected, scattered, and/or transmitted by an optical component), traditional monitors use a photodiode or similar photo sensing device to detect the optical signal""s presence. A separate photo sensing device is typically necessary for each optical signal. The detected optical signal is typically processed in the form of logging an optical signal""s absence or presence.
One disadvantage with current optical signal detection is the necessity for a separate photo detector for each optical signal. The requirement of a separate photo detector for each optical signal results in an increase in complexity and cost associated with manufacturing, assembling and operating an optical signal monitor.
A second disadvantage of traditional optical signal detectors is the use of, for example, copper wire to electronically communicate the detected optical signal to a processor. Copper wire is susceptible to EMI (electromagnetic interference), and as a result, it is not recommended to use copper wire to communicate detected signals in applications where EMI may produce false signals to the processor. Therefore, some applications are not able to use optical signal monitors which utilize copper wire or electronic signals.
The present invention provides a monitor for multiple optical signals. The optical signals from various optical generators are combined together to form an array of optical signals. The array is imaged and the image is processed to detect the presence of the various optical signals.
The invention, in one form thereof, is an apparatus for monitoring a plurality of optical signals. At least one optical signal generator produces at least one of the plurality of optical signals. The apparatus includes fiber optics having at least one fiber, the fiber has a first end and a second end. The first end is operatively associated with one of the plurality of optical signals, and the second end terminates at an array. An optical sensor means is operatively associated with the array for generating an array signal. A processor means is operatively associated with the array signal for detecting a quality of the optical signals communicated through the fibers. In varying alternate embodiments, the optical signal generator is an optical reflection off of an optic such as a mirror, transmissive optical component, polarizer, or gain medium. In addition, the optical generator may be a flashlamp, amplified stimulated emission from gain medium, fluorescence from a gain medium, or a target backscattering event. In alternate embodiments, the quality of the optical signal detected is the absence or presence, intensity, or wavelength of the optical signal.
The invention, in a further, alternate embodiment thereof, includes a second fiber optic, a second optical sensor means, and a second processor means. The processor means and the second processor means generate a first processor signal and a second processor signal respectively. A central processor is operatively associated with the first processor signal and the second processor signal. The central processor generates a central processor signal.
The invention, in another form thereof, is a method of monitoring a plurality of optical signals. The method includes the steps of providing fiber optics which have an origin operatively associated with an optical signal generator and a termination forming an array. The plurality of optical signals are captured from the array to generate at least one captured signal. A quality of at least one of the plurality of optical signals from at least one captured signal is detected.
One advantage of the present invention is the ability to detect a plurality of optical signals simultaneously. An array of optical signals is imaged and the image is processed to detect the absence or presence of an optical signal.
A second advantage of the present invention is a decrease in the cost to implement this monitor over current optical signal detection systems. Traditional optical detectors use a separate photodiode or similar detector for each optical signal. As the number of optical signals increases, the costs associated with the numerous photodiodes and data collection equipment becomes prohibitively high. The present invention eliminates the need for a separate photodiode or other detector for each optical signal by imaging and processing an array of optical signals. Consequently, the costs, physical space, electrical connections, and digital data acquisition equipment associated with individual photodiodes are eliminated.
A third advantage of the present invention is the use of fiber optics rather than electrical wire, e.g. copper wire. Since fiber optics are not susceptible to EMI, the present invention is suitable for employment in applications where electrical wire based monitors could not be employed.
A fourth advantage of the present invention is that the operation costs of a laser system implementing the invention should decrease since the laser operator will be monitoring the laser system in real-time rather than running separate diagnostics on the laser system.